import java.io.*;

/**
 *
 将一个字符串str的内容颠倒过来，并输出。str的长度不超过100个字符。 如：输入“I am a student”，输出“tneduts a ma I”。
 *
 *
 * @author: YuanChilde
 * @date: 2020-02-17 8:01
 * @version: 1.0
 * Modification History:
 * Date    Author      Version     Description
 * -----------------------------------------------------------------
 * 2020-02-17 8:01    YuanChilde     1.0        新增
 */
public class Demo24 {

        public static int getCount(int n,int m) {
            int[][] dp=new int[n+1][m+1];
            for(int i=0;i<n+1;i++) {
                for(int j=0;j<m+1;j++) {
                    if(i==0||j==0) dp[i][j]=1;
                    else dp[i][j]=dp[i][j-1]+dp[i-1][j];
                }
            }
            return dp[n][m];
        }
        public static void main(String[] args)throws IOException {
            BufferedReader bReader = new BufferedReader(new InputStreamReader(System.in));
            String line=null;
            while((line=bReader.readLine())!=null) {
                int n=Integer.valueOf(line.substring(0,line.indexOf(" ")));
                int m=Integer.valueOf(line.substring(line.indexOf(" ")+1));
                System.out.println(getCount(n, m));
            }
        }
}
